JP3931296B2 - 4-DOF parallel robot - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a four-degree-of-freedom parallel robot.
[0002]
[Prior art]
Conventionally, a four-degree-of-freedom parallel robot is disclosed in Japanese Patent Laid-Open No. 2001-88072. This four-degree-of-freedom parallel robot is shown in FIG. As shown in FIG. 8, the traveling plate 4 includes a main member 41, a pair of connecting members 42, and a pair of pivots that connect an intermediate portion of each connecting member 42 to both ends of the main member 41 so as to be rotatable about a vertical axis. 43.
[0003]
[Patent Document 1]
JP 2001-88072 A
[0004]
[Problems to be solved by the invention]
However, the conventional four-degree-of-freedom parallel robot has the following problems. First, as shown in FIG. 9A, as the main member 41 is rotated, the distance between the connecting members 42 is shortened. Thus, the change in the distance between the connecting members 42 depending on the rotation angle of the main member 41 greatly changes the mechanical characteristics. A large change in mechanical properties causes a deterioration in controllability. Further, as shown in FIG. 9B, when the main member 41 is greatly rotated, the connecting member 42 may interfere. Therefore, it is necessary to limit the rotation angle of the main member (rotating part) 41 so that the connecting member 42 does not interfere. Further, the mounting direction of the four sets of rod members 3 to the traveling plate 4 must be an appropriate direction in order to avoid singularities. As a result, the degree of freedom in design is reduced. Furthermore, since the forward kinematics is not established in an analytical form except for special cases, the position angle control of the main member 41 will perform the convergence calculation of the forward kinematics, which will increase the calculation time. It causes deterioration of controllability.
[0005]
The present invention has been made in view of such circumstances, improves controllability, reduces the rotation angle limit of the rotating portion, and further allows freedom in designing the mounting direction of the rod member to the traveling plate. An object of the present invention is to provide a parallel robot with a large degree of freedom.
[0006]
[Means for Solving the Problems and Effects of the Invention]
The four-degree-of-freedom parallel robot of the present invention includes a base, four actuators, four sets of rod members, and a traveling plate. Here, the actuator has a fixed part fixed to the base and a movable part pivotally supported by the fixed part. One end of the rod member is connected to the movable portion of each actuator via a first rotary joint that can swing and rotate. The traveling plate has a plate portion and a rotating portion. The plate portion is a member that is connected to the other end side of each rod member via a second rotary joint that can swing and rotate, and is movable in three orthogonal directions with respect to the base. The rotating part is a member that is supported by the plate part and is rotatable around a predetermined axis with respect to the base.
[0007]
And the characteristic structure of this invention is that the said plate part is provided with the 1st plate part, the 2nd plate part, and the linear motion joint, and the said rotation part was provided with the rotation means. A 1st plate part is a plate by which the other end side of two sets of rod members was connected via the 2nd rotation joint among four sets of rod members. A 2nd plate part is a plate which supports the rotation part rotatably so that the other end side of other 2 sets of rod members among 4 sets of rod members may be connected via the 2nd rotation joint. The linear motion joint is a joint in which the first plate portion and the second plate portion are coupled so as to be capable of relative translation. The rotating means is means for rotating the rotating portion around a predetermined axis by relative translation of the first plate portion and the second plate portion.
[0008]
That is, when rotating the rotating part, the first plate part and the second plate part relatively translate. Accordingly, the distance between the first plate portion and the second plate portion is always kept constant. Thereby, the following effects are produced. First, according to the present invention, the mechanical characteristics that have changed greatly as the distance between the connecting members 42 shown in FIG. As a result, controllability is improved. Furthermore, conventionally, the problem of interference of the connecting member 42 has occurred, but according to the present invention, the first plate portion and the second plate portion do not interfere with each other. As a result, the rotation angle of the rotating part due to interference is not limited. Furthermore, there are few restrictions on the mounting direction of the four rod members to the traveling plate due to singular points, and the degree of freedom in designing the mounting direction is increased. For example, the rod member can be attached in a symmetrical direction. Furthermore, since forward kinematics can be obtained in an analytical form, the calculation time is shortened, resulting in improved controllability.
[0009]
The rotating means may comprise a pinion gear disposed on the outer peripheral side of the rotating portion and a rack gear disposed on the rotating portion side of the first plate portion and meshing with the pinion gear. That is, the rotation means in this case is a rack and pinion mechanism. Thereby, while being able to transmit rotation reliably, rotation angle control of a rotation part can be performed correctly. Furthermore, the rotational speed can be freely changed by changing the gear ratio. Moreover, durability can be improved compared with the conventional structure.
[0010]
The rotating means may be a cable wound around the outer peripheral surface of the rotating portion and fixed at both ends to the first plate portion. That is, the rotating means in this case is a cable wheel mechanism. In addition, a rotation part will rotate with the frictional force of a cable and a rotation part. As described above, since the rotating portion can be rotated only by the cable, there is almost no backlash like a gear, the rotating motion of the rotating portion can be made quiet, and further, the cost can be reduced.
[0011]
The four-degree-of-freedom parallel robot of the present invention includes a base, four actuators, four sets of rod members, and a traveling plate. The characteristic configuration of the present invention is that the plate portion includes a first plate portion, a second plate portion, a third plate portion, a first linear motion joint, and a second linear motion joint. In other words, the rotating section includes rotating means. Here, a 1st plate part is a plate by which the other end side of two sets of rod members was connected via the 2nd rotation joint among four sets of rod members. A 2nd plate part is a plate with which the other end side of the other 2 sets of rod members was connected via the 2nd rotation joint among 4 sets of rod members. The third plate portion is a plate that rotatably supports the rotating portion. The first linear motion joint is a joint in which the first plate portion and the third plate portion are coupled so as to be capable of relative translation. The second linear motion joint is a joint in which the second plate portion and the third plate portion are coupled so as to be capable of relative translation. The rotating means is means for rotating the rotating portion around a predetermined axis by relative translation between the first plate portion and the third plate portion and relative translation between the second plate portion and the third plate portion. .
[0012]
That is, when rotating the rotating part, the first plate part and the second plate part relatively translate through the third plate part. Accordingly, the distance between the first plate portion and the second plate portion is always kept constant. Thereby, there exists an effect similar to the effect mentioned above. In addition, since the first plate portion and the second plate portion can be formed in the same shape, an operation balance can be achieved and controllability is further improved. Furthermore, forming the first plate portion and the second plate portion in the same shape also leads to a reduction in manufacturing cost.
[0013]
The rotating means includes a pinion gear disposed on the outer peripheral side of the rotating portion and a rack gear disposed on the rotating portion side of the first plate portion and / or the second plate portion and meshing with the pinion gear. Also good. That is, the rotation means in this case is a rack and pinion mechanism. Thereby, while being able to transmit rotation reliably, rotation angle control of a rotation part can be performed correctly. Furthermore, the rotational speed can be freely changed by changing the gear ratio. Moreover, durability can be improved compared with the conventional structure. The rack gear may be disposed on both the first plate portion and the second plate portion, or may be disposed on either the first plate portion or the second plate portion. When the rack gears are arranged on both sides, the rotation angle control can be performed more accurately.
[0014]
The rotating means includes a first cable wound around the outer peripheral surface of the rotating portion and fixed at both ends to the first plate portion, and wound at the outer peripheral surface of the rotating portion and fixed at both ends to the second plate portion. You may make it consist of a 2nd cable. That is, the rotating means in this case is a cable wheel mechanism. In addition, a rotation part will rotate with the frictional force of a cable and a rotation part. As described above, since the rotating portion can be rotated only by the cable, there is almost no backlash like a gear, the rotating motion of the rotating portion can be made quiet, and further, the cost can be reduced.
[0015]
Also mentioned above Four sets Of the rod members, at least three sets of rod members are composed of two parallel rods constituting a parallel link, and each rod is connected to an actuator on one end side and connected to a traveling plate on the other end side. Also good. Further, at least one of the first rotary joint and the second rotary joint may be a ball joint. By these, it can be ensured that the rotating part has four degrees of freedom.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to embodiments.
[0017]
(First embodiment)
FIG. 1 shows an overall configuration diagram of a four-degree-of-freedom parallel robot in the present embodiment. As shown in FIG. 1, the four-degree-of-freedom parallel robot includes a base 1, four sets of actuators 2, four sets of rod members 3, a traveling plate 4, and an end effector 5 (shown in FIG. 2). Have.
[0018]
The base 1 is a highly rigid metal plate or frame having a substantially rectangular planar shape, and is disposed horizontally. The four actuators 2 are composed of linear motors, and are composed of two rail portions (fixed portions) 21 and four movable elements (movable portions) 22. Each rail portion 21 extends in parallel with the horizontal direction in the horizontal direction of FIG. 1 and is fixed to the base 1 and is magnetized alternately. The mover 21 moves along the rail portion 21 below the rail portion 21 and has an electromagnetic coil inside. There are four moving elements 22, and two moving elements 22 are attached to each rail of the rail portion 21. That is, one actuator 2 means one rail 21 and one moving element 22. The actuators 2 are independently controlled by a control device (not shown).
[0019]
The four sets of rod members 3 include a pair of rods 31, an upper end member 32, a ball joint (first rotation joint) 33, a lower end member 34, and a universal joint (second rotation joint) 35. The upper end member 32 is connected and fixed to the mover (movable part) 22 of each actuator 2. The pair of rods 31 constitute parallel links arranged in parallel to each other. One end of each rod 31 is connected to an upper end member 32 through a ball joint 33 so as to be swingable and rotatable. On the other hand, the other end side of each rod 31 is connected to a lower end member 34 through a universal joint 35 so as to be swingable and rotatable. That is, the parallelogram is always formed by each rod 31, the upper end member 32, and the lower end member 34. The upper end member 32 and the lower end member 34 have the same length. The lower end member 34 is connected to the traveling plate 4.
[0020]
The traveling plate 4 will be described with reference to FIGS. 2 and 3. FIG. 2 is a perspective view of the traveling plate 4 as seen from the bottom surface direction. FIG. 3 is a schematic view seen from the bottom surface direction of the traveling plate 4. 2 and 3, the traveling plate 4 includes a main member 41, connecting members 42 and 43, linear motion joints 44 and 45, a rotating member (rotating portion) 46, and a rack gear (rotating portion and rotating portion). Means) 47 and 48 and a pinion gear (rotating part, rotating means) 49.
[0021]
The main member (third plate portion) 41 has a substantially rectangular shape, and a through hole is formed at the center. The connecting members 42 and 43 (the first connecting member (first plate portion) 42 and the second connecting member (second plate portion) 43) have a substantially isosceles triangular shape, and the first connecting member 42 and the second connecting member. It arrange | positions so that the base of 43 may oppose. And the lower end member 34 is being fixed to the other side of the 1st connection member 42 and the 2nd connection member 43, respectively. Specifically, two sets of lower end members 34 are attached to the two sides excluding the bottom side of the first connecting member 42, and the remaining two sets of lower end members 34 exclude the bottom side of the second connecting member 43 2. Attached to the side. That is, the first and second connecting members 42 and 43 can swing and rotate with respect to each rod 31 via the universal joint 35.
[0022]
The linear motion joints 44 and 45 include a fixed rail and a slider that slides on the fixed rail, and connects the main member 41 and the connecting members 42 and 43. Specifically, the fixed rail of the first linear motion joint 44 is attached to the lower side of the first connecting member 42 in FIG. 1, and the slider of the first linear motion joint 44 is on the upper surface side of the main member 41 in FIG. It is attached. In other words, the main member 41 can be relatively translated with respect to the first connecting member 42. Further, the fixed rail of the second linear motion joint 45 is attached to the lower side of the second connecting member 43 in FIG. 1, and the slider of the second linear motion joint 45 is attached to the upper surface side of the main member 41 in FIG. Yes. That is, the main member 41 can be relatively translated with respect to the second connecting member 43. That is, the first connecting member 42 and the second connecting member 43 are relatively translated through the linear motion joints 44 and 45 and the main member 41.
[0023]
The rotating member 46 is pivotally supported in a through hole of the main member 41 via a bearing (not shown). That is, the rotation member 46 can rotate around the Z axis (up and down in FIG. 1).
[0024]
The first rack gear 47 is fixed to the side of the first connecting member 42 facing the second connecting member 43. The second rack gear 48 is fixed to the side of the second connecting member 43 that faces the first connecting member 42. The pinion gear 49 is fixed to the outer peripheral side of the rotating member 46 and meshes with the first rack gear 47 and the second rack gear 48. That is, when the first connecting member 42 and the second connecting member 43 are relatively translated, the rotating member 46 rotates via the first and second rack gears 47 and 48 and the pinion gear 49.
[0025]
As shown in FIG. 2, the end effector 5 is fixed to the lower end side of the rotating member 46 of the traveling plate 4. The end effector 5 can be exchanged according to the application of the four-degree-of-freedom parallel robot, and control signals and power are supplied to the end effector 5 via signal lines and power lines (not shown). The signal line and the power line may be appropriately supported and suspended from the base 1, or may be disposed along any one of the arms 23 and the parallel link 3. The end effector 5 is, for example, a handling device for transferring a workpiece or supporting it at a predetermined position, or a tool of a machine tool for applying machining to the workpiece.
[0026]
Here, the direction of the lower end member 34 of the parallel link 3 attached to the traveling plate 4 is 45 °, 135 °, with reference to the longitudinal direction of the fixed rails of the linear motion joints 44, 45, as shown in FIG. The directions are 225 ° and 315 °. However, it is not restricted to these directions and can be attached in any direction.
[0027]
Next, the operation of the four-degree-of-freedom parallel robot configured as described above will be described. First, the case where the rotation angle θ of the end effector 5 is 0 ° and the end effector 5 moves in the orthogonal three-axis direction with respect to the base 1 will be described. In this case, since the end effector 5 does not rotate, it is not necessary to rotate the rotating unit 46. Accordingly, the relative positions of the first connecting member 42 and the second connecting member 43 are fixed.
[0028]
Based on the position of the end effector 5, the position of the moving element 22 is calculated by a control device (not shown). Each moving element 22 moves horizontally along the rail portion 21 based on the calculated position of the moving element 22. Then, the traveling plate 4 is moved through the parallel link 3 by the movement of each moving element 22 and the end effector 5 is moved to a predetermined position. In this case, the end effector 5 always moves while facing downward.
[0029]
When the rotation angle θ of the end effector 5 is not 0 °, the relative positions of the first connection member 42 and the second connection member 43 change according to the rotation angle θ. Here, in FIG. 3, when the first connecting member 42 moves to the left with respect to the second connecting member 43, the rotating member 46 rotates counterclockwise via the first and second rack gears 47 and 48 and the pinion gear 49. Rotate to. That is, based on the rotation angle θ of the end effector 5 and the position of the end effector 5, the position of the mover 22 is calculated by the control device. In the same manner as described above, the traveling plate 4 moves based on the position of the mover 22 calculated by the control device.
[0030]
Thus, even if the rotation angle θ of the end effector 5 is not 0 °, the first connecting member 42 and the second connecting member 43 always maintain a constant distance. As a result, the operating range of the end effector 5 is the same as in the conventional case when the rotation angle θ of the end effector 5 is 0 °, but a difference occurs as compared with the conventional case as the rotation angle θ of the end effector 5 increases. come. Specifically, in the four-degree-of-freedom parallel robot of this embodiment and the conventional four-degree-of-freedom parallel robot, the operation range becomes narrower as the rotation angle θ of the end effector 5 increases. However, the reduction amount of the operation range of the end effector 5 of the present embodiment is smaller than the reduction amount of the operation range of the conventional end effector 5.
[0031]
Furthermore, since the first connecting member 42 and the second connecting member 43 always maintain a certain distance, they do not interfere with each other. In other words, the operating range is conventionally limited by interference, but this is not necessary. The lengths of the linear motion joints 44 and 45 and the rack gears 46 and 47 can be freely adjusted. Further, as described above, the attachment direction of the lower end member 34 of the parallel link 3 attached to the traveling plate 4 can be freely selected, so that the degree of design freedom increases. Furthermore, since the forward kinematics can be obtained in an analytical form, the calculation time is shortened, and as a result, the controllability can be improved.
[0032]
In addition, since each rail part 21 of the actuator 2 consisting of a linear motor extends in the horizontal direction and is parallel to each other, the traveling plate 4 is moved along the rail part 21 as long as the rail part 21 exists. Can do. As a result, there is an effect that the moving range of the traveling plate 4 is greatly extended in the horizontal direction along the rail portion 22.
[0033]
Further, since the position of the upper end member 32 of the parallel link 3 is moved only in the horizontal direction and not moved in the vertical direction, a simple link mechanism is obtained. Therefore, the calculation processing algorithm for coordinate conversion for calculating the target position of the moving element 22 of the actuator 2 made of a linear motor from the target position of the traveling plate 4 is further simplified, and the calculation load of the control device is reduced.
[0034]
(Modification of Embodiment 1)
In the first embodiment, a linear motor is used as the actuator 2. However, the present invention is not limited to this. For example, the overall configuration of the four-degree-of-freedom parallel robot may be the configuration illustrated in FIG. Here, the configuration of the four-degree-of-freedom parallel robot shown in FIG. 4 will be described.
[0035]
The four-degree-of-freedom parallel robot shown in FIG. 4 includes a base 1 ′, four sets of actuators 2 ′, four sets of rod members 3, a traveling plate 4, and an end effector 5 (shown in FIG. 2). .
[0036]
The base 1 ′ is a highly rigid metal plate having a substantially regular octagonal plan shape, and is disposed horizontally, and the upper surface side is fixed to a frame (not shown). The four actuators 2 'are composed of a bracket (fixed part) 21', a rotary motor 22 ', a rotary shaft 23', and an arm (movable part) 24 '. The bracket 21 'is fixed at a predetermined position at a predetermined angle on the lower surface side of the base 1'. The rotation motor 22 ′ is a servo motor, is fixed to the bracket 21 ′, and is independently controlled by a control device (not shown). The rotating shaft 23 ′ is rotatably supported by the bracket 21 ′ and is rotated by driving of the rotating motor 22 ′. One end of the arm 24 ′ is connected and fixed to substantially the center of the rotation shaft 23 ′, and the other end is connected to the rod member 3. The arm 24 'swings within a predetermined angular range as the rotating shaft 23' rotates.
[0037]
The four sets of rod members 3 have the same configuration as that of the above embodiment, and include a pair of rods 31, an upper end member 32, a ball joint (first rotary joint) 33, a lower end member 34, and a universal joint (second joint). Rotary joint) 35. The upper end member 32 is connected and fixed to the other end side of the arm (movable part) 24 ′ of each actuator 2 ′. The pair of rods 31 constitute parallel links arranged in parallel to each other. One end of each rod 31 is connected to an upper end member 32 through a ball joint 33 so as to be swingable and rotatable. On the other hand, the other end side of each rod 31 is connected to a lower end member 34 through a universal joint 35 so as to be swingable and rotatable. That is, the parallelogram is always formed by each rod 31, the upper end member 32, and the lower end member 34. The upper end member 32 and the lower end member 34 have the same length. The lower end member 34 is connected to the traveling plate 4.
[0038]
And since the traveling plate 4 and the end effector 5 are the same as the said embodiment, description is abbreviate | omitted.
[0039]
Next, the operation of the four-degree-of-freedom parallel robot configured as described above will be described. First, the case where the rotation angle θ of the end effector 5 is 0 ° and the end effector 5 moves in the orthogonal three-axis direction with respect to the base 1 will be described. In this case, since the end effector 5 does not rotate, it is not necessary to rotate the rotating unit 46. Accordingly, the relative positions of the first connecting member 42 and the second connecting member 43 are fixed.
[0040]
Based on the position of the end effector 5, the rotation angle of each rotary motor 22 'is calculated by a control device (not shown). Each rotary motor 22 'rotates based on the calculated rotation angle of the rotary motor 22'. As the rotary motors 22 'rotate, the arm 24' swings around the rotary shaft 23 '. As the arm 24 'swings, the traveling plate 4 moves via the parallel link 3 to move the end effector 5 to a predetermined position. In this case, the end effector 5 always moves while facing downward.
[0041]
When the rotation angle θ of the end effector 5 is not 0 °, the relative positions of the first connection member 42 and the second connection member 43 change according to the rotation angle θ. Here, in FIG. 3, when the first connecting member 42 moves to the left with respect to the second connecting member 43, the rotating member 46 rotates counterclockwise via the first and second rack gears 47 and 48 and the pinion gear 49. Rotate to. That is, based on the rotation angle θ of the end effector 5 and the position of the end effector 5, the rotation angle of each rotation motor 22 ′ is calculated by the control device. In the same manner as described above, the traveling plate 4 moves based on the rotation angle of each rotary motor 22 ′ calculated by the control device.
[0042]
The four-degree-of-freedom parallel robot having such a configuration also has the same effect as the above embodiment.
[0043]
(Second Embodiment)
Next, a four-degree-of-freedom parallel robot in the second embodiment will be described with reference to the drawings. Here, the four-degree-of-freedom parallel robot in the second embodiment is different only in the traveling plate 4 of the four-degree-of-freedom parallel robot in the first embodiment, so only that portion will be described.
[0044]
As shown in FIG. 5, the traveling plate 5 includes a first plate portion 51, a second plate portion 52, a linear motion joint 53, a rotating member (rotating portion) 54, and a cable (rotating means) 55. Is done. Two sets of lower end members 34 are fixed to the first plate portion 51. The 2nd plate part 52 consists of a substantially triangular shape, and the through-hole is formed in one corner | angular part. And two other sets of lower end members 34 are fixed to the other corners. That is, the first plate portion 51 and the second plate portion 52 can swing and rotate with respect to each rod 31 via the universal joint 35.
[0045]
The linear motion joint 53 includes a fixed rail and a slider that slides on the fixed rail, and connects the first plate portion 51 and the second plate portion 52. Specifically, the fixed rail of the linear motion joint 53 is attached to the first plate portion 51, and the slider of the linear motion joint 53 is attached to the second plate portion 52. In other words, the first plate portion 51 can be relatively translated with respect to the second plate portion 52.
[0046]
The rotating member 54 is pivotally supported in the through hole of the second plate portion 52 through a bearing (not shown) so as to be rotatable. That is, the rotation member 54 can rotate around the Z axis.
[0047]
The cable 55 is wound around the outer peripheral surface of the rotating member 54, and both end sides are fixed to the first plate portion 51. The cable 55 is arranged substantially in parallel with the linear motion joint 53 while maintaining a predetermined tension. That is, when the first plate portion 51 and the second plate portion 52 are relatively translated, the rotating member 54 can be rotated by the frictional force of the cable 55.
[0048]
(Third embodiment)
Next, a four-degree-of-freedom parallel robot in the third embodiment will be described with reference to the drawings. Here, the four-degree-of-freedom parallel robot in the third embodiment is different only in the traveling plate 4 of the four-degree-of-freedom parallel robot in the first embodiment, so only that portion will be described.
[0049]
As shown in FIG. 6, the traveling plate 6 includes a main member (third plate portion) 61, a first connecting member (first plate portion) 62, a second connecting member (second plate portion) 63, The first linear motion joint 64, the second linear motion joint 65, a rotating member (rotating unit) 66, a first cable (rotating unit) 67, and a second cable (rotating unit) 68 are configured.
[0050]
The main member 61 has a substantially rectangular planar shape, and a through hole is formed at the center. The first connecting member 62 and the second connecting member 63 have the same shape, and two sets of lower end members 34 are fixed thereto. That is, the first and second connecting members 62 and 63 can swing and rotate with respect to each rod via the universal joint 35.
[0051]
The first linear motion joint 64 and the second linear motion joint 65 include a fixed rail and a slider that slides on the fixed rail. The main member 61 and the connecting members 62 and 63 are connected. Specifically, the fixed rail of the first linear motion joint 64 is attached to the first connecting member 62, and the slider of the first linear motion joint 64 is attached to the main member 61. That is, the main member 61 can be relatively translated with respect to the first connecting member 62. The fixed rail of the second linear motion joint 65 is attached to the second connecting member 63, and the slider of the second linear motion joint 65 is attached to the main member 61. That is, the main member 61 can move relative to the second connecting member 63. That is, the first connecting member 62 and the second connecting member 63 are relatively translated through the linear motion joints 64 and 65 and the main member 41.
[0052]
The rotating member 66 is rotatably supported in the through hole of the main member 61 via a bearing (not shown). That is, the rotation member 66 can rotate around the Z axis.
[0053]
The first cable 67 is wound around the outer peripheral surface of the rotating member 54, and both end sides are fixed to the first connecting member 62. The first cable 67 is disposed in a state where a predetermined tension is maintained substantially parallel to the first linear motion joint 64. That is, when the main member 61 and the first connecting member 62 are relatively translated, the rotating member 64 can be rotated by the frictional force of the first cable 67.
[0054]
Similarly to the first cable 67, the second cable 68 is wound around the outer peripheral surface of the rotating member 54, and both end sides are fixed to the second connecting member 63. The second cable 68 is disposed substantially in parallel with the second linear motion joint 65 while maintaining a predetermined tension. That is, when the main member 61 and the second connecting member 63 are relatively translated, the rotating member 64 can be rotated also by the frictional force of the second cable 67. That is, when the first connecting member 62 and the second connecting member 63 are relatively translated, the rotating member 46 is rotated by the first and second cables 67 and 68.
[0055]
(Fourth embodiment)
Next, a four-degree-of-freedom parallel robot in the fourth embodiment will be described with reference to the drawings. Here, the four-degree-of-freedom parallel robot in the fourth embodiment is different from the rod member 3 and the traveling plate 4 of the four-degree-of-freedom parallel robot in the first embodiment. Only the differences will be described below.
[0056]
Of the four sets of rod members 3, the three sets of rod members 3 constitute a parallel link including a pair of rods 31, an upper end member 32, a ball joint 33, a lower end member 34, and a universal joint 35. That is, the three sets of rod members 3 are the same as the rod members shown in the first embodiment. The remaining set of rod members 3 is arranged on one rod (not shown), a first ball joint (not shown) disposed on the upper end side of the rod, and on the lower end side of the rod. And a second ball joint 36 (shown in FIG. 7). The first ball joint is connected to the other end of the arm 24 (shown in FIG. 1), and the second ball joint 36 is connected to the traveling plate 5 (shown in FIG. 7).
[0057]
The traveling plate 7 is almost the same as the traveling plate 5 shown in the second embodiment. However, the second plate portion 52 is connected to a pair of rod members 3 that constitute a parallel link of the rod members 3 and a second ball joint of the rod member 3 that does not constitute a parallel link.
[0058]
The operation of the four-degree-of-freedom parallel robot configured as described above is the same as that shown in the first and second embodiments.
[0059]
(Other embodiments)
In the above-described embodiment, the rod member 3 has the ball joint 33 disposed on the upper end side of the rod 31 and the universal joint 35 disposed on the lower end side of the rod 31, but is not limited thereto. Absent. For example, a universal joint may be disposed on the upper end side of the rod 31 and a ball joint may be disposed on the lower end side of the rod 31. Further, ball joints may be disposed on both ends of the rod 31.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a four-degree-of-freedom parallel robot according to a first embodiment.
FIG. 2 is a perspective view showing a traveling plate in the first embodiment.
FIG. 3 is a schematic diagram of a traveling plate in the first embodiment.
FIG. 4 is a diagram illustrating a four-degree-of-freedom parallel robot according to a modification of the first embodiment.
FIG. 5 is a perspective view showing a traveling plate in the second embodiment.
FIG. 6 is a perspective view showing a traveling plate in a third embodiment.
FIG. 7 is a perspective view showing a traveling plate in a fourth embodiment.
FIG. 8 is a diagram illustrating a conventional four-degree-of-freedom parallel robot.
FIG. 9 is a view showing an operating state of a conventional traveling plate.
[Explanation of symbols]
1,1 '... base
2, 2 '... Actuator
3 ... Rod member
4, 5, 6, 7 ... Traveling plate
33, 36 ... Ball joint
35 ・ ・ ・ Universal joint
44, 45, 53, 64, 65 ... linear motion joints
47, 48 ... Rack gear
49 ・ ・ ・ Pinion gear
55, 67, 68 ... Cable

Claims (8)

The base,
Four actuators having a fixed part fixed to the base and a movable part pivotally supported by the fixed part;
Four sets of rod members, one end side of which is connected to the movable part of each of the actuators via a first rotary joint that can swing and rotate;
A plate part connected to the other end of each rod member via a second rotary joint that can swing and rotate, and movable in three orthogonal directions with respect to the base, and supported by the plate part on the base A traveling plate having a rotating part rotatable around a predetermined axis;
In a four-degree-of-freedom parallel robot with
The plate portion is
A first plate portion in which the other end side of two sets of the rod members among the four sets of rod members is connected via the second rotary joint;
A second plate part that is connected to the other end side of the other two sets of rod members among the four sets of rod members via the second rotary joint and rotatably supports the rotary part;
A linear motion joint connected to the first plate portion and the second plate portion so as to be capable of relative translation;
The rotating part is
A four-degree-of-freedom parallel robot, comprising: rotating means for rotating the first plate portion and the second plate portion around the predetermined axis by relative translation of the first plate portion and the second plate portion. The base,
Four actuators having a fixed part fixed to the base and a movable part pivotally supported by the fixed part;
Four sets of rod members, one end side of which is connected to the movable part of each of the actuators via a first rotary joint that can swing and rotate;
A plate part connected to the other end of each rod member via a second rotary joint that can swing and rotate, and movable in three orthogonal directions with respect to the base, and supported by the plate part on the base A traveling plate having a rotating part rotatable around a predetermined axis;
In a four-degree-of-freedom parallel robot with
The plate portion is
A first plate portion in which the other end side of two sets of the rod members among the four sets of rod members is connected via the second rotary joint;
A second plate portion in which the other two ends of the other two sets of the rod members among the four sets of the rod members are connected via the second rotary joint;
A third plate portion that rotatably supports the rotating portion;
A first linear motion joint connected to the first plate portion and the third plate portion so as to be capable of relative translation;
A second linear motion joint connected to the second plate portion and the third plate portion so as to be capable of relative translation;
The rotating part is
Rotating means for rotating around the predetermined axis by means of relative translation between the first plate portion and the third plate portion and relative translation between the second plate portion and the third plate portion. A four-degree-of-freedom parallel robot. The rotating means includes
A pinion gear disposed on the outer peripheral side of the rotating part;
A rack gear disposed on the rotating portion side of the first plate portion and meshing with the pinion gear;
The four-degree-of-freedom parallel robot according to claim 1, comprising: The rotating means includes
A pinion gear disposed on the outer peripheral side of the rotating part;
A rack gear disposed on the rotating part side of the first plate part and / or the second plate part and meshing with the pinion gear;
The four-degree-of-freedom parallel robot according to claim 2, comprising: The rotating means includes
2. The four-degree-of-freedom parallel robot according to claim 1, wherein the four-degree-of-freedom parallel robot is a cable wound around an outer peripheral surface of the rotating portion and having both ends fixed to the first plate portion. The rotating means includes
A first cable wound around an outer peripheral surface of the rotating portion and having both end sides fixed to the first plate portion;
The four-degree-of-freedom parallel robot according to claim 2, comprising a second cable wound around an outer peripheral surface of the rotating portion and having both ends fixed to the second plate portion. Among the four sets of rod members, at least three sets of the rod members are composed of two parallel rods constituting a parallel link,
3. The four-degree-of-freedom parallel robot according to claim 1, wherein each of the rods has one end connected to the actuator and the other end connected to the traveling plate. The four-degree-of-freedom parallel robot according to claim 1, wherein at least one of the first rotary joint and the second rotary joint is a ball joint.

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